Various types of magnetoresistive random access memory (MRAM) store data using magnetic tunnel junctions. A magnetic tunnel junction (MTJ) may include “fixed” and “free” magnetic layers, where a magnetic moment of the free layer may be switched to be parallel or antiparallel to a magnetic moment of the fixed layer. A thin dielectric or barrier layer may separate the fixed and free layers, and current may flow across the barrier layer due to quantum tunneling. A difference in resistance between parallel and antiparallel states allows data to be stored. For example, a low resistance may correspond to a binary “1” and a high resistance may correspond to a binary “0,” Alternatively, a low resistance may correspond to a binary “0” and a high resistance may correspond to a binary “1.”
In a cross-point memory array, a cell may be accessed using a first conductive line coupled to a row of cells, and a second conductive line coupled to a column of cells. For example, a data value may be read from a cell by applying a voltage to a row line and sensing the current at the column line, to determine the resistance of the cell. However, the current at the column line may be affected by “sneak current” through other cells in the array. Sneak current may disturb data in neighboring cells during a write operation, reduce the reliability of read operations, and increase the overall power consumption (and heat generation) of a memory device. Accordingly, certain memory devices may include switching or selection components such as transistors, Zener diodes, or the like, which limit leakage current through unselected cells. However, selection components may add area to an array, thus decreasing the density of cells and overall storage capacity. Additionally, selection components that limit sneak current during read and write operations may reflect a compromise between desired characteristics for read operations, write operations, and endurance.